Wireless communication may be used to transfer information over many distances, ranging from short distances (a few meters as in television remote control) to long distances (thousands or millions of kilometers for radio communications). Wireless communication encompasses various types of fixed, mobile, and portable two-way radios, cellular telephones, personal digital assistants (PDAs), and wireless networking. Typical wireless devices communicate according to predetermined communication protocols, such as IEEE communication standards or other telecommunications standards, for example. Although there are many different communication standards, any given standard specifies precise rules for communication, thereby helping to ensure that wireless devices from different manufacturers communicate effectively with one another.
Modern wireless communication devices are integrating more and more communication functions into a single device. For example, a single conventional mobile phone can transmit and receive data using multiple communication standards, such as 2G and 3G telecommunication standards. These standards can require different transmission powers, different modulation techniques, different transmission frequencies, and the like.
In order to allow a single wireless device to transmit according to different communication standards, conventional wireless communication devices include multiple transmission paths and/or reception paths. For example, FIG. 1 shows a portion of a conventional wireless transceiver 100 that includes a first transmission path 102 on which a 3G signal is transmitted and a second transmission path 104 on which a 2G signal is transmitted. Both transmission paths 102, 104 include digital to analog converters (DACs) 106 and mixers 108, wherein low-pass filters 110 are disposed between the DACs 106 and their corresponding mixers 108.
For a reasonable current consumption, a 3G vector modulator is weak in noise performance, so inter-stage surface acoustical wave (SAW) filters 112 are required for each transmission band, as shown in FIG. 2. These SAW filters 112 are coupled between the output of transmission path 102 (which supports multiple transmission bands, e.g., TX—3G_H, TX—3G_L, TX—3G_M1), and corresponding power amplifiers (PA) 114 used for transmission over the corresponding bands. The need for the different SAW filters 112 increases the pin count of the transceiver 100, as well as the size of the printed circuit board (PCB), and the overall bill of materials (BOM).
In view of these conventional communication devices, the inventors have appreciated that it would be helpful from a cost and power perspective to provide a single, flexible transmission path that is shared for multiple communication standards rather than using separate transmission paths for each communication standard. Also, it would be beneficial to eliminate the need for SAW filters to reduce the pin count of the transceiver, the size of the printed circuit board (PCB), and the overall bill of materials (BOM) used for the transceiver.